左连接没有结果

Question

这是两张桌子.

tbl_Invoice

tbl_Payment

我想要的是Pending Invoices一个特定的客户.

现有查询如下:

Select * from tbl_Invoice I 
    left join tbl_payment P on I.client_id = P.client_id
    left join tbl_client C on I.client_id = C.client_id
    where I.invoice_Id not in (P.invoice_Id) 
    and I.client_id = 8

但它给出了空白结果,因为付款表是空白的.

Answer 1

您需要将条件WHERE移至ON:

Select * from tbl_Invoice I 
left join tbl_payment P on (I.client_id = P.client_id 
 AND p.invoice_id <> I.invoice_Id)
left join tbl_client C on I.client_id = C.client_id

WHERE I.client_id = 5